DESCRIPTION: (Applicant's abstract)The need for a cancellous bone substitute, in the form of an artificial biocompatible implant, is significant. Research has demonstrated that an implant ideally should serve as a porous framework for bone regeneration. In this program, Ultramet proposes a novel biomedical application of a material originally developed for nonmedical purposes. Reticulated carbon foam will be infiltrated with tantalum by chemical vapor infiltration (CVI), a variation of the chemical vapor deposition (CVD) process. Tantalum has a long history of use as an implant material, in both bone and soft tissue. In Phase I, Ultramet will demonstrate the feasibility of producing tantalum foams in several porosities and configurations, and the CVI process for tantalum will be refined and initially optimized. The materials fabricated by Ultramet will then be evaluated by the Department of Bioengineering, Clemson University, which will conduct extensive mechanical testing and corrosion studies. The results of the mechanical tests performed on reticular tantalum will be compared to accepted values for cancellous bone.This lightweight, strong, porous structure, mimicking the microstructure of natural cancellous bone, will act as a matrix for the incorporation of bone, providing optimal permeability and a high surface area to encourage new bone ingrowth.